Materials, documents and people may move into both desirable and undesirable locations. For example, a hazardous material may be put near another hazardous material, increasing the potential hazard. Similarly, a person may move into a hazardous or restricted area, either without authorization or simply by mistake. Similarly, documents may be taken to places they should not go, or shown to people who should not see them.
Alternatively, all of these examples may be prevented through use of tracking technology. Providing a method to intelligently warn against co-location of hazardous materials may be useful. Similarly, providing a method of independently determining whether a person is authorized to enter an area may be useful. Moreover, providing a method of tracking movement of a document may be useful. Tracking of the document may be related to making sure the document only goes where it should, and may also be related to verifying the authenticity of signatures on a document, for example.